British Columbia 2018 Lingcod Egg Mass Survey. A male lingcod guarding an egg mass. Photo by: Audrey Garbacik

Transcription

1 British Columbia 218 Lingcod Egg Mass Survey A male lingcod guarding an egg mass Photo by: Audrey Garbacik Laura Borden & Jeff Marliave Ocean Wise June 218

2 A Brief History of Lingcod in British Columbia Lingcod have an extensive history of commercial and recreational exploitation, and were once the fourth major commercial fishery in British Columbia (Cass et al 199)Throughout the last century, lingcod have undergone biomass reduction from commercial fishing In the late 198s, lingcod stocks in the Strait of Georgia collapsed to approximately 3-% of original biomass, with Howe Sound stocks reaching a low 1% of original biomass (Martell and Wallace, ) As a result, the Strait was closed to commercial fishing in 199, with sport fishing regulations established in 1992 Even with these precautionary actions implemented, the depressed state of lingcod abundance was still a concern and thus Porteau Cove and Whytecliff Park were designated as a no-take closure area in 1993 under the Fisheries Act of Canada In, all sport fishing for lingcod was banned in the Strait of Georgia and surrounding waters This ban was lifted on the east coast of Vancouver Island in but remains in place for the Vancouver area (area 28 and 29-1, 29-4 and 29-6 to 29-17) In 27 the Department of Fisheries and Oceans Canada (DFO) established 164 Rockfish Conservation Areas (RCAs) in British Columbia, in order to provide protection for BC s inshore rockfish populations (Yamanaka and Logan ), which are severely depleted following decades of unsustainable harvesting These RCAs also provide protection for and assist in the recovery of local lingcod populations Owing to extreme low abundance of lingcod in Howe Sound and Burrard Inlet, all hook-and-line fishing for groundfish (lingcod and rockfish) was banned in summer of 27 Lingcod spawn from December through to early April in the Strait of Georgia, with peak egg mass abundance in late February The males guard the egg masses, which resemble styrofoam, for over a month until hatching The behavior of the guarding male and the distinctive appearance of the egg masses are easily identified by SCUBA divers Dives logged during the annual Lingcod Egg Mass Survey are performed by recreational divers as well as staff from Ocean Wise Divers are enlisted through a variety of sources including dive organizations, stores, charters, magazines, and personal contacts For the most part, dives by Aquarium staff have been limited to Howe Sound Biology of Lingcod Lingcod spawn primarily in January/February in crevices on rocky shores of western North America where strong currents allow for egg respiration (Cass et al, 199) Eggs are adhesive to each other and resemble a clump of styrofoam Females can begin to spawn at three years old and their egg masses are approximately one liter volume A four-year female will lay an egg mass of about 2-2 liters, and then beyond five-years old, the fish lay much larger egg masses (Giorgi 1981) In 199 reference sizes were created based on whether the egg mass resembled the size of a grapefruit (under one liter, from a 3-yr female), a cantaloupe (ca two liters, from 4-yr female), or watermelon (- yr or older) Most lingcod spawning occurs within a depth range safe for scuba diving (often between 1-6ft) Most nests are guarded by the male parent, although smaller males tend to flee temporarily when approached by seals or divers Smaller males may sneak in and partially fertilize some eggs during spawning, so a spawning reef often has more male lingcod than nests The guarding male is the fish that attracted the female and initiated courtship and spawning, and is usually the principal sire of the egg mass A dominant male may guard two or three adjacent egg masses, usually separately by no more than 1m (Cass et al, 199) The guarding behavior of the male parent tends to indicate the location of the eggs, which vary from white when newly laid to dark gray toward hatching If the egg mass remains lodged in a crevice where currents force water flow through the eggs, and the male remains to prevent predation, embryos survive to the hatching stage of development

3 Photo of male lingcod guarding egg mass Eggs incubate for -11 weeks depending on temperature and current flow (Cass et al, 199) Hatch success varies with strength of currents: egg mortality occurs from respiratory failure in low flows Newly hatched larvae swim rapidly to the surface, orient into currents and swim offshore by selecting stronger currents This takes them into tidal current drift and rapidly disperses them through the spawning area Little is known about the extent of larval dispersal, but over-fished areas do not seem to receive any rescue effect from spawning populations in remote areas Adults are relatively sedentary, with only the females showing a seasonal depth migration for summer feeding Within two to three months of hatching, larvae settle at about 7 mm length and start feeding on juvenile herring Lingcod reach 21 cm length in their first year, 3 cm at 2 months age, and 4 cm (8 kg weight) in their third year, as two-year olds (age 2+) Males grow rapidly until 8 years age, and live to a maximum of approximately 14 years Females grow until years age, and live to approximately 2 years An age 13 male averages 84 cm and 61 kg, versus an age 13 female that averages 13 cm and 119 kg The size record is 1 cm and 32 kg Female lingcod of 1-12 years age are about twice the weight of males that age Survey Instructions This year marked the 2 th anniversary of the Lingcod Egg Mass Survey (LEMS) Initiated in the winter of 1994 by the Marine Life Sanctuaries Society (MLSS), the survey encourages divers from the community to census spawning of lingcod along the BC coast Since, Ocean Wise has promoted and collated data for the census, encouraging a record number of participants

4 The Lingcod Egg Mass Survey occurs over a five-week period centered on the third weekend in February, a time when most lingcod egg masses have been spawned but not much hatching has occurred Divers are given an information packet that has all the pertinent information to complete the census; this packet is available online ( or by contacting Ocean Wise For each dive the following information is recorded: Date - The month/day/year Diver Information - The first and last names of both divers and all pertinent contact information Area - There are 2 polygon areas we have divided the coast into; please note the appropriate area Dive Site - Divers often identify sites by local names, which can make it difficult for us to know where the data were collected Identify the specific location you are diving in and provide a GPS point if possible (ex: Whytecliff Park Marker) Bottom Time - Note the bottom time for your dive and if only a portion of the dive was spent looking for egg masses, note that time Comments - Be sure to record if no egg masses are found or if the dive was primarily on soft bottom (versus bedrock or boulders) Nest Information Depth Note the depth where you found the egg mass in feet Size Estimate if the egg mass is roughly the size of a Grapefruit, Cantaloupe or Watermelon (G, C, W) Condition You may want to bring a dive light along with you This will aid in determining the condition of the egg mass Recently extruded eggs will generally be white/pink (N=New) Older eggs will be eyed/dark grey (E=Eyed), or rotten (R=Rotten) Situation Note how the egg mass is situated, either loose (L) in a crevice, secure (S) in a crevice, or loose in the open (O) Nest Guarding Male Often one male may guard more than one egg mass If the male is guarding only one egg mass, indicate so with a P If the male is guarding multiple egg masses, indicate so with P2 If this is observed, record each egg mass as an individual egg mass and be sure to indicate the nest guarding male as P2 for each egg mass If there is an egg mass without a guarding male, indicate the absence of the male with A Sample dive slate with nest information: Nest # Depth (ft) Size Condition Situation Nest Guarding Male 1 18 W N S P W E S P2 3 2 C R O A 4 3 G E L P 32 W N O A 6 33 C E S P All data are sent to the Vancouver Aquarium or entered online Once we have sorted the data we calculate the index of abundance by using a Count Per Unit Effort (CPUE) The CPUE is the number of egg masses sighted per hour and is calculated by multiplying the number of egg masses by 6 to get an hourly sighting rate, divided by the dive time Please return data reports promptly to ensure a timely summary report

5 Results and Discussion The 2 th annual lingcod egg mass survey was conducted between January 27 th and March 11 th, 218 Divers from all across British Columbia and Ocean Wise staff undertook 11 dives totaling 4,676 minutes underwater In all, 326 egg masses were seen by divers; 61 were seen inside Howe Sound and the remaining 26 were seen on dives in areas outside Howe Sound (table 1) Figure 1 Geographic area breakdown for British Columbia south coast and Washington, comprised of 2 unique polygons Areas are defined based on long-term biodiversity records

6 No Egg Masses (No h-1 diving) Over the course of 2 years of surveying spawning lingcod populations in British Columbia s south coast, there is little indication of an increase in lingcod abundance The 2-year average abundance of egg masses is 434 h -1 survey (Fig 2) The 218 survey results are closely aligned with the long-term average with divers recording an average of 418 egg masses h -1 (Fig 2) Similarly, the percentage of egg masses produced by the largest females which produce the most viable larvae has been ~% over the course of the past 2 years, reaching 9% in 218 (Fig 3) The 2-year history of this survey shows that the smallest age group of spawning females, which produce grapefruit size egg masses, represent less than 2% of the population, while 4-year-old females consist of 3-4% of the spawning population Despite a lack of trend with regard to female spawning population structure, there are clear differences on a smaller geographic scale Four areas had at least ten surveys contributed in 218 to provide a sufficient sample size for comparison: Northern Gulf Islands, Parksville, Howe Sound and Barkley Sound Of these four areas, only Howe Sound had an abundance of lingcod egg masses above the 2-year average, with divers recoding 69 egg masses h -1 (table 1) However, despite this abundance being above-average and an increase from 217 survey results, only 7% of these egg masses were guarded by males The absence of a male lingcod guarding an egg mass greatly reduces the likelihood of eggs reaching the hatching stage Without the male, it is likely that the eggs would be consumed by predators, such as urchins or sea stars By comparison, the next lowest percentage of guarded egg masses was 79%, for areas with at least ten surveys For areas such as northeast Vancouver Island where the spawning lingcod population appears healthy, egg mass guarding is frequently at or above 9% At the sites located along northeast Vancouver Island and surveyed since, the spawning female population has done exceedingly well every year Divers have noted egg masses that are twice the size of a watermelon, indicating they were produced by old reproductive females This population of lingcod provides an important comparison for all other areas Figure 2 Abundance of lingcod throughout British Columbia s south coast since 1994, measured as the number of egg masses seen per hour diving Solid line indicated average for each survey year Dashed line indicates 2-year average

7 218 Egg Mass Size (%) 1 8 Watermelon Canteloupe Grapefruit Figure 3 Percentage of egg masses produced by + year old females (blue), 4-year-old females (red), and 3-year-old females (green) throughout British Columbia s south coast since 1994 Selected sites Lingcod have larger home ranges than rockfish, but are unlikely to stray more than 1km from where they settle as juveniles (Cass et al, 199) Examining lingcod population abundance and spawning population structure at specific sites provides an opportunity to understand year-over-year changes on a much smaller geographic scale We ve selected five sites where data for this survey have been collected for at least ten years, representing four areas with an extensive history surveying spawning lingcod populations (Fig 4) At Whytecliff Park designated as an MPA in 1993 there has only once been an abundance of lingcod in line with the 2-year average (Fig 4a) Most frequently there is only a single egg mass, and often none, at Whytecliff Park As a result of the low abundance of egg masses, there is no pattern in the age structure of the female lingcod population as determined by egg mass size (Fig a) By comparison, the other MPA located further into Howe Sound, Porteau Cove, has seen between -1 egg masses h -1 since surveys began there in (Fig b) Abundance of egg masses in 218 was below average at just 348 egg masses h -1 Size distribution of egg masses at Porteau Cove is in line with overall survey averages, with approximately -6% of egg masses recorded as watermelon-sized At Nash Bank in the northern gulf islands, surveys of spawning lingcod have been conducted since Egg mass abundance has been remarkably consistent over the past 1 years at this site, with an average of 4 egg masses h -1 survey (Fig 4d) Similar to the overall long-term average, Nash Bank has an average of approximately % watermelon-sized egg masses, while the least common size of egg mass is grapefruit In contrast to the consistency of egg mass abundance at Nash Bank, the abundance and size distribution of egg masses at Tyler Rock in Barkley Sound has been variable since the first surveys were conducted at that site in (Fig 4c & Fig c) Egg mass abundance was slightly lower in 218 at Tyler Rock, 69 h -1, compared to 21 when the last lingcod egg mass surveys were conducted at the reef As previously mentioned, the spawning lingcod population at sites along northeast Vancouver Island have done exceedingly well over the past 18 years Abundance of spawning lingcod at Five Fathom Rock one of two sites with consistent surveying in the area has reliably had around 2

8 218 Egg Mass Sighting (h-1) Egg Mass Sightings (h -1 ) Egg Mass Sightings (h -1 ) egg masses h -1 survey (Fig 4e) In addition, nearly 1% of these masses are produced by females at least years of age (Fig e) The consistently high abundance of lingcod at this site represents population demography closest to historical values What each of these individual sites demonstrates is the high variability in lingcod egg mass abundance we see among different areas within the Strait of Georgia and Outer Coast of Vancouver Island While some areas do consistently well and are populated predominantly by large females, many have significant year-to-year variation There doesn t appear to be any indication of a shift toward an older female population for most surveyed areas either In order to see a significant recovery of lingcod stocks from the low reached in the 199s, we would hope to see an increase in the number of large females which produce the greatest number of and most viable young a b c d e Figure 4 Abundance of lingcod egg masses (count per unit effort) since at (a) Whytecliff Park, and (b) Porteau Cove in Howe Sound, (c) Tyler Rock in Barkley Sound, (d) Nash Banks in the Northern Gulf Islands, and (e) Five Fathom Rock along northeast Vancouver Island NB the scale for Five Fathom Rock is significantly greater to accommodate the high abundance of egg masses unique to this area

9 218 Egg Mass Size (%) Egg Mass Size (%) 218 Egg Mass Size (%) a b c 1 d watermelon Canteloupe Grapefruit e Figure Distribution of egg mass size since at (a) Whytecliff Park and (b) Porteau Cove in Howe Sound, (c) Tyler Rock in Barkley Sound, (d) Nash Banks in the Northern Gulf Islands, and (e) Five Fathom Rock along northeast Vancouver Island Threats The two main threats to lingcod population recovery are illegal fishing practices and predators, including seals and sea lions Lingcod populations face pressure from recreation fishing likely due to a combination of lack of knowledge of fishing restrictions and difficulty of enforcement by the

10 Department of Fisheries and Oceans (DFO) A 2/ enforcement campaign along the Sea-to- Sky Highway by DFO resulted in an increase in egg mass abundance for Howe Sound in, showing that enforcement can have a direct impact on spawning numbers Whytecliff Park, despite being designated as an MPA in 1993, is a prime example of an area where frequent poaching has been seen due to the ease of access for the metropolitan Vancouver population In addition to illegal fishing pressures, populations of harbor seals have increased in the past decade or so and are a potential reason for the continued suppression of lingcod spawning numbers, though no analysis of seal diets has been conducted since the 198s for areas such as Howe Sound Solutions In 27,164 rockfish conservation areas were established along the British Columbia coast, which aim to protect BC s depleted inshore rockfish stocks and also lingcod In addition, there is a complete commercial and recreational fishery closure for area 28 and parts of area 29 (Howe Sound and Burrard Inlet) for lingcod and rockfish Follow the existing regulations for fishing in your area and report any violations to the Department of Fisheries and Oceans Canada (DFO: ) How can you help? Since its inception in 1994, the lingcod egg mass survey has been strongly dependent on divers from the community surveying rocky shoreline for lingcod egg masses from January to March What started as a citizen science initiative of the Marine Life Sanctuary Society remains largely dependent on contributions from the diving community This year 81 divers from across the southern coast of British Columbia participated in the survey, comprising 87% of all dives conducted Divers can contribute to this survey by submitting their dives online during the annual Lingcod Egg Mass Survey ( The Lingcod Egg Mass Survey is not the only census the Coastal Ocean Research Institute s Howe Sound Research Program conducts Since, prior to the announcement of the first Rockfish Conservation Areas (RCAs) in, researchers for Ocean Wise have been conducting Rockfish Abundance Surveys Since 213 the majority of contributions to the survey effort have come from citizen science divers throughout British Columbia The Howe Sound Research Program promotes the Rockfish Abundance Survey (RAS) August October annually For more information visit the survey webpage: wwwvanaquaorg/rockfish Please see the LEMS 218 results table on the following page

11 Table 1 Summary, by area, of lingcod egg mass sightings along the British Columbia south coast in winter 218 # of Total Total egg % % Area Dives Minutes Masses CPUE %W %C %G Secured guarded Barkley Sound Campbell River Howe Sound Inside Southern Gulf Islands NE Vancouver Island Northern Gulf Islands Parksville Saanich Inlet Strait of Georgia Outside HS Strait of Juan de Fuca Victoria all References Martell SJD and S S Wallace Estimating historical lingcod abundance in the Strait of Georgia Pages 4 47 in D Pauly and D Preikshot, eds Back to the future: reconstructing the Strait of Georgia ecosystem Fisheries Centre, Univ British Columbia, Vancouver 211 p Cass, AJ, RJ Beamish, and GA McFarlane 199 Lingcod (Ophiodon elongatus) Can Spec Publ Fish Aquat Sci 19: 4 p Yamanaka, K L and G Logan Developing British Columbia's Inshore Rockfish Conservation Strategy, Marine and Coastal Fisheries, 2:1, Giorgi, AE, 1981 The environmental biology of the embryos, egg masses and nesting sites of the lingcod, Ophiodon elongates Natural Marine Fisheries Services NWAFC Processed Rep 81-6:17p